Counting and Grouping (Kindergarten)
Practice math in the backyard with this for outdoor math activity, Addition With Rocks, which uses rocks as a math manipulative to work on adding.
Use rocks with sticks for division symbol, sticks make x and +. This is a great way to introduce the concept of tally marks to kids. Lots of great math ideas and activities for young kids.
Finding Symmetry in Nature (Outdoor Math Activity for Kids) - Buggy and Buddy